And yet the new system — which is designed to be more sophisticated, more helpful, and provide more accountability — nonetheless produced dramatically different results in the Tampa Bay area and the state.

For example, Hillsborough County calls 41.5 percent of its teachers "highly effective," but only 5.3 percent of Pinellas teachers and 3.6 percent in Pasco get rated so highly. In Hernando County, 16.8 get the high rating.

Pinellas County rates 17.8 percent of its teachers in the "needs improvement" category, more than any large county in Florida, and far more than the 2.1 percent statewide.

Variation is built into the system because school districts created their own scorecards for rating educators within mandates laid down by the Legislature.

The complexity of the system came into focus Wednesday when the Department of Education posted its first round of numbers, then took them down after realizing thousands of teachers had been double counted, creating inaccuracies.

In Tallahassee Thursday, interim state Education Commissioner Pam Stewart fielded questions from members of the Senate's Education Appropriations Subcommittee about whether the faulty data was evidence of an unreliable system.

"I think any time you implement something this large for the first time, there are growing pains," Stewart said.

The department contacted all counties in the state and released the corrected information late Thursday. Most percentages concerning teacher evaluations changed only slightly, if at all.

In the new system, school districts must base evaluations partly on the "value added model," which compares student learning gains to the expectations for similar students around the state.

The idea is to rate teachers based on how well students are actually learning, and to push educators to get even better results than one would expect.

Much of the controversy comes from the details more than the concept itself. In many cases this year, the student learning was measured using the FCAT. And because students in many grades don't take the FCAT, and the test doesn't cover all subjects, many teachers were evaluated on the learning gains of students who weren't even in their classrooms.

"Clearly when you're being scored on students you've never taught, the system was flawed from the start," said Marshall Ogletree, executive director of the Pinellas Classroom Teachers Association.

This is an issue Education Commissioner Stewart knows firsthand. Her daughter teaches kindergarten in a district that doesn't have an assessment for kindergartners to measure educational growth, so the district uses school-wide information on the premise that every teacher has an impact on the success of the school. Until they have a measure for growth of kids in her daughter's classroom, this is how they will evaluate her.

"In year one, that is one of the things that we're facing that is problematic for us," Stewart said. "That is one of the biggest concerns that we hear and will be corrected each year as we move forward with this system and as the assessments are developed and used in districts."

The data produced varying reactions.

"Today marks the first step in a long journey toward identifying and recognizing the contributions of Florida's best teachers," said state Sen. John Legg, R-Trinity, chairman of the Education Committee.

"Yet another blow to our hardworking teachers," said the Florida Education Association.

Counties are taking different approaches. In Pinellas, superintendent Mike Grego is scheduled to discuss possible changes to the district's system during a workshop Tuesday.

The situation is different in Hillsborough, which started its reform effort a year ahead of the rest of the state, assisted by a $100 million grant from the Bill and Melinda Gates Foundation for what it calls Empowering Effective Teachers, or EET.

Now, more than 95 percent of teachers are considered effective or highly effective and "we're completely comfortable with that," said spokesman Stephen Hegarty.

EET also has a mentoring component, and district officials say that feature has greatly reduced turnover in first-year teachers.

In Hernando County, superintendent Bryan Blavatt has concerns with the way the data is collected but said, overall, he was okay with the evaluations.